Dynamic molecular design for liquid-crystalline materials with a fast response speed

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1.Development of nematic liquid crystals for display devices : A novel U-shaped liquid-crystalline molecule where two polar mesogenic groups are connected via catechol,1-{6-(3,4-difluorophenyloxy)hexyloxy}-2-{6-[4-(4-fluorophenyl)phenyloxy]hexyloxy}benzene, was prepared and the electrooptic properties were investigated. The threshold voltage of a nematic mixture consisted of a host liquid crystal (LC) and 10wt% of the U-shaped compound was found to be markedly lower than that of the host LC. Marked reduction in threshold voltage by the compound was found to be attributed to the increase in dielectric anisotropy. The U-shaped system is a novel approach for the reduction in the threshold voltage of liquid-crystalline materials.2.Novel chiral liquid crsyatls with a broad blue phase region : We designed chiral liquid crystal oligomers possessing molecular biaxiality. We prepared a homologous series of (R)-2,2'-bis{6-[4-(2-(2-fluoro-4-butyloxyphenyl)pyrimidine-5-yl)phenyloxy]alkyloxy}-1,1'- … More binaphthyl. The binaphthyl derivatives with an even number of atoms in the spacers showed a chiral nematic phase, however, those with an odd number of atoms showed a blue phase in a relatively wide temperature range between the isotropic and SmA phases. Then, we prepared a T-shaped compound, (R)-1-methylhepthy1-4'-{4-octyloxy-2-{11-[4-(5-octylpyrimidin-2-yl)phenoxy]undecanoyloxy}benzoyloxy}biphenyl-4-carboxylate, which was found to show a blue phase with a wide temperature range on cooling.3.Liquid crystal oligomers with a hierarchical structure : A homologous series of novel λ-shaped mesogenic compounds in which three mesogenic groups are connected to 3,4-dihyrdoxybenzoic acid has been prepared. 4-Cyanobiphenyl-4'-yl 3,4-bis{6-[4-(5-octylpyrimidm-2-yl)phenyloxy]hexyloxy}behzoate was found to realize an incommensurate SmA (SmAinc) phase. We prepared a homologous series of bimesogenic liquid crystals, α-(4-cyanobiphenyl-4'-yloxy)-ω-[4-(5-alkylpyrimidine-2-yl)phenyl-4"-oxy]alkane (mPYnOCB). The interdigitated anticlinic smectic C (SmCanti) phase was found to be induced for some binary mixtures betweeen the bimesogenic compounds with a different odd-numbered spacer. Furthermore, a striped pattern was observed in the SmCanti phase of a homeotropically aligned sample. The striped pattern was propagated when the temperature of the sample was varied. Less